The molding process includes a certain amount of cooling or cure time before the mold can be opened and the molded article can be removed. In specific applications the geometry of the molded article is such that it during the cooling process it will shrink away from the cavity side of the mold and form around the core side of the mold. Prior art takes advantage of this characteristic of the molding process by moving the core that the molded article is formed around away from the injection position prior to completion of the cooling portion of the process to one or more cooling positions and then subsequently to an ejection position once the cooling portion of the molding process is completed. The cooled mold article is then removed from the core.
Movement of the core with the molded part formed around it is typically achieved through the use of a rotating turret block incorporated into the mold or as part of the injection molding press. A typical mold system of the prior art is illustrated in FIG. 10.
The problem with such prior art systems is that they limit the overall processing cycle time by requiring enough cooling to allow the molded article to be shrink away from the cavity side of the mold. The second problem with prior art is that is not applicable for molded articles that require convective heat removal from both the cavity and core sides of the mold. The third problem with prior art is that it is only applicable for molded articles with distinct part geometry that will allow the molded article to shrink and form around the core side of mold and stay attached to the core side during the movement of the core. The fourth problem with prior art is that isn't applicable for molded articles that have cavity side features as well as core side features that the molded article can shrink around. The fifth problem with prior art is that it is not always applicable for molded articles that have cavity undercuts or other part features that must be formed by mechanical movements such as cams or lifts on the cavity side of the mold halves